1. Field of the Invention
This invention relates to making tubular joint connections and more particularly to an improvement in a stabbing guide construction for assisting in making such connections.
2. Description of the Prior Art
The connecting ends of lengths of tubular goods are referred to as the pin end and the box end. When consecutive joints are connected together in making up a string of such joints, it is normal that one joint is suspended above the other in an appropriate holding and handling rig and then lowered so that the pin end "stabs" into the box end. The external surface area of the pin end and the receiving internal surface area of the box end primarily comprise the helical threads that make up the connection and the sealing and supporting surfaces that are located contiguous to the thread sets.
When the pin end, for example, of one tubular joint is stabbed into the box end of the adjacent joint, it is very common for the joints not to be perfectly axially aligned or for that matter for the centerline of one joint to be at a slight angle to the centerline of the other joint. Moreover, the holding and handling apparatus normally employed does not normally position the joint being manipulated with precision or without considerable force. Therefore, when the pin end is stabbed into the box end, threads are often damaged or broken and the supporting and sealing shoulders and other surfaces are often scarred, resulting in poor connections and causing pressure leaks and the like.
It has long been recognized that stabbing damage could be reduced or avoided altogether by the use of an appropriate stabbing guide. Such a guide normally is made to fit around the stationary joint end, normally the box end, thereby to both cushion the stabbing impact as well as to position or direct the handled end, normally the suspended joint with its pin end down, so that it funnels into makeup position within the accommodating box end without destructive consequences. Such guides are usually enclosed either in a two-part housing releasable by a catch-and-hinge arrangement or in a split one-piece flexible housing releasably held in place by a single catch. A guide is put in position by handles located on each of the two split hinged halves or affixedly located on opposite sides of the split for the one-piece type guide.
The guides, also sometimes referred to as protectors, have employed either resilient material, for example rubber or a rubber-like equivalent, or a material that was softer than the threads of the tubular goods being joined, for example, aluminum for protecting and guiding steel threaded ends. Because the guides or protectors themselves are subject to potentially damaging forces, they are destroyed or rendered non-effective after substantial use. It has also been recognized, heretofore, that by making guides so that they could accommodate or accept suitable replaceable inserts or linings, the life of the substantial housing or outer carrier portion of a guide could be greatly extended.
Tubular goods used in oil and gas production come in various sizes, all the way from large casings to relatively small drill pipe. A guide suitable for one size pipe or tubular goods is not suitable for use with another size pipe or tubular goods. If guides were placed in inventory for all goods that might be employed at a particular location, the inventory of sizes of such guides might well be substantial. It is sometimes difficult to get crews to use stabbing guides at all because it represents an additional handled item apart from all other apparatus employed. By asking such crews to keep and maintain a large inventory of separate guides, it makes regular and routine use of stabbing guides even more improbable, resulting in an increase of damaged joint ends and the putting in service of ends making faulty connections.
Therefore, it is a feature of the present invention to provide a stabbing guide having a housing and a replaceable insert suitable for use with a range of tubular goods, rather than just one size.
It is another feature of the present invention to provide a stabbing guide having a plurality of internal resilient projections, preferably in the form of foldover fingers, that accommodate to a range of outside dimension tubular products, while centering all such products within the range.
It is still another feature of the present invention to provide a stabbing guide with a replaceable insert useful for accommodating a range of sizes of pipe or other tubular goods having an entry larger than the outside diameter dimension of the sleeve portion of the insert within the housing.